Stator for rotary machine and method of manufacturing the stator

ABSTRACT

A stator for a rotary machine includes a rotor  7  and a stator  8  having a stator iron core  15  disposed oppositely around the outer circumference of the rotor  7  and a stator coil  16  fitted around the iron core  15,  wherein the iron core  15  has a laminated iron core  150  with plural axially extending slots  15   a  formed circumferentially at predetermined pitches, an insulating resin  100  is coated on an axial end face  15   f  of the iron core  15  and an inner wall face of a slot  15   a  in the laminated iron core  150  to provide insulation between the iron core  15  and the stator coil 16, and the iron core is cylindrically shaped by bringing both circumferential end portions  15   g  of the laminated iron core  150  into contact to bend the laminated iron core  150  so that an opening face 15 b  of the slot  15   a  is directed inside.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a stator for a rotary machinethat is driven by an internal combustion engine for the vehicle, forexample, and a method for manufacturing the stator.

[0003] 2. Description of the Related Art

[0004]FIG. 13 is a perspective view showing the conventional rotarymachine (alternator for vehicle) as disclosed in U.S. Pat. No. 3078288,for example. In FIG. 13, a rotor 7 of landau type is rotatably attachedvia a shaft 6 within a case 3 composed of a front bracket 1 and a rearbracket 2, and a stator 8 is supported on an inner wall face of the case3 to cover the outer circumferential side of the rotor 7. The shaft 6 isrotatably supported by the front bracket 1 and the rear bracket 2. Apulley 4 is secured at one end of this shaft 6 to allow a rotationaltorque of the engine to be transmitted via a belt (not shown) to theshaft 6. A slip ring 9 for supplying a current to the rotor 7 is securedto the other end of the shaft 6, and a pair of brushes 10 areaccommodated within a brush holder 11 disposed within the case 3 toslide with the slip ring 9. A regulator 18 for regulating the magnitudeof an AC voltage produced in the stator 8 is connected to a heat sink 17fitted with a brush holder 11. A rectifier 12 electrically connected tothe stator 8 for rectifying the alternating current produced in thestator 8 to the direct current is mounted within the case 3.

[0005] The rotor 7 comprises a rotor coil 13 for producing a magneticflux by passing a current, and a pair of pole cores 20, 21, provided tocover the rotor coil 13, for forming the magnetic poles due to themagnetic flux produced by the rotor coil 13. One pair of pole cores 20,21 made of iron have eight pawl-like magnetic poles 22, 23 projectedaround the outer circumferential edge at an equiangular pitch in acircumferential direction, and are oppositely secured to the shaft 6 tomate the pawl-like magnetic poles 22, 23. Further, the fans 5 aresecured to both axial ends of the rotor 7. Also, the suction holes 1 a,2 a are provided on the axial end faces of the front bracket 1 and therear bracket 2, and the exhaust holes 1 b, 2 b are provided on bothshoulder portions of the front bracket 1 and the rear bracket 2 aroundthe outer circumference, opposed to the radial outside of the coil endgroups 16 a, 16 b on the front side and the rear side of the stator coil16.

[0006] The stator 8 comprises a stator iron core 15 composed of acylindrical laminated iron core with a plurality of axially extendingslots 15 a being formed at a predetermined pitch in the circumferentialdirection, a polyphase stator coil 16 wound around the stator iron core15, and an insulating paper 19, fitted with in each slot 15 a, forelectrically insulating between the polyphase stator coil 16 and thestator iron core 15 as shown in FIG. 14. And the polyphase stator coilgroup 16 has a plurality of coils, each of which is wave wound to takealternately an inner layer and an outer layer in a slot depth directionwithin the slot 15 a for every predetermined number of slots, oneelement wire 30 being folded back outside the slot 15 a on the end faceside of the stator iron core 15. Herein, the stator iron core 15 toreceive two pairs of three-phase stator coils 16, corresponding to thenumber of magnetic poles (16) for the rotor 7, so that 96 slots 15 a areformed at equal interval. For the element wire 30, a long copper wirematerial having a rectangular cross section covered with an insulatedmaterial is employed, for example.

[0007] A method for manufacturing the stator 8 will be specificallydescribed below with reference to FIGS. 15 to 21. First of all, 12 longelement wires 30 are bent like a thunder on the same plane at the sametime, as shown in FIG. 15. Then, they are folded over by a jig in aright angle direction, as indicated by the arrow in FIG. 16, and anelement wire group 30A is fabricated as shown in FIGS. 17A and 17B.Similarly, an element wire group 30B having a transition connection anda lead wire are fabricated, as shown in FIGS. 18A and 18B. The elementwire groups 30A, 30B are composed of six pairs of element wires, shiftedby one slot pitch, each pair of element wires being arranged in such away that two element wires 30 formed in this pattern are shifted by apitch of 6 slots from each other and superposed in a straight part 30 b,as shown in FIG. 21. And six end wires of the element wire 30 extend outon either side at either end of the element wire groups 30A, 30B. Also,the turn portions 30 a are aligned at either side portion of the elementwire groups 30A, 30B.

[0008] On the other hand, a certain number of main laminated plates 15 dmade of an SPCC material having a trapezoidal slot 15 a and the teeth 15c formed at a predetermined pitch (an electrical angle of 30°) arelaminated, and laser welded at a predetermined position on the outercircumference, thereby producing a laminated iron core 150 of roughlyrectangular parallelopiped.

[0009] As shown in FIGS. 20A and 21, the insulating paper 19 is fittedinto the slot 15 a of an iron core 36, each straight section of twoelement wire groups 30A, 30B superposed being pushed into each slot 15a. Thereby, two element wire groups 30A, 30B are attached around thelaminated iron core 150, as shown in FIG. 20B. At this time, thestraight portion 30 b of the element wire 30 is insulated from thelaminated iron core 150 by the insulating paper 19, and accommodatedwithin the slot 15 a, four wires being aligned radially. Also, twoelement wire groups 30A, 30B are fitted in superposition around thelaminated iron core 150, as shown in FIG. 21. Then, the laminated ironcore 150 is rounded, the end faces 15 being brought into contact witheach other and welded together, whereby the cylindrical stator 8 isproduced as shown in FIG. 20C.

[0010] However, in the conventional alternator for the vehicle, sincethe insulation between the stator coil group 16 and the stator iron core15 was made by the insulating paper 19, as described above, there was aproblem that the material cost of the insulating paper 19 was taken, agreater number of steps were required, and the costs were increased.Also, there was a further problem that the insulation process such ascoating was required as another step on a portion where the iron coreportion was exposed, thereby increasing the number of steps.

[0011] At a step of forming the stator iron core 15 cylindrically, anexcessive stress occurs in the teeth 15 c of the stator iron core 15,and a laminated steel plate making up the teeth 15 c is deformed andshifted circumferentially on the inner diameter side of the stator ironcore 15, disordering a magnetic circuit, resulting in a problem of loweroutput voltage. And since the insulation between the stator iron core 15and the stator coil 16 is made by the insulating paper 19, when theteeth 15 c is deformed, the insulating paper 19 is ruptured, resultingin a problem of causing a short-circuit with the stator coil 16.

[0012] When the stator coil group 16 is inserted in the slot 15 a of thestator iron core 15 in a direction of the arrow A, as shown in FIG. 21,or when molding the stator iron core cylindrically, as shown in FIG.20C, a reaction force from the stator coil group 16 is exerted. Inparticular, the stator iron core 15 is molded cylindrically around theneutral axis on the almost central portion of the core pack, whereaseach coil group 16 is deformed cylindrically around the neutral axis ofeach coil group 16. Therefore, the displacement of the stator iron core15 and each coil group 16 are different, so that a greater stress isexerted on the teeth 15 c. Accordingly, a contact occurs between theopening edge of the axial end face for the stator iron core 15 and thestator coil group 16, and the insulating paper and the insulation filmfor the stator coil group 16 are exfoliated, resulting in a problem ofcausing a pressure-proofing failure.

[0013] Further, the insulating paper 19 is interposed between the statoriron core 15 and the stator coil group 16, whereby there is a gapbetween the inner wall face of the slot 15 a and the insulating paper19. Therefore, due to an insulation failure caused by a dislocation wheninserting the stator coil group 16, or the water content permeating intothe gap, or a bad thermal conduction (coolness) between the stator coilgroup 16 that is a heat generating body and the stator iron core 15,there was a problem that the alternator for vehicle was degraded inquality.

SUMMARY OF THE INVENTION

[0014] This invention has been achieved in the light of theaforementioned problems, and it is an object of the invention to providea stator for a rotary machine and a method for manufacturing the stator,in which the stator has a high insulation and cooling performance, andcan be produced in simple manner, with high quality and lower costs.

[0015] To achieve the above object, according to this invention, thereis provided a stator for a rotary machine comprising a rotor and astator having a stator iron core disposed oppositely around the outercircumference of the rotor and a stator coil fitted around the statoriron core, wherein the stator iron core has a laminated iron core with aplurality of axially extending slots formed at a predetermined pitchalong a circumferential direction, an insulating resin is coated atleast on an axial end face of the stator iron core and an inner wallface of a slot in the laminated iron core to provide insulation betweenthe stator iron core and the stator coil, and the laminated iron core isformed in a cylindrical shape by bringing both circumferential endportions of the laminated iron core into contact with each other in sucha way as to bend the laminated iron core so that an opening face of theslot on the inner circumferential side may be directed inside.

[0016] The insulating resin is coated to be thicker on the axial endface of the stator iron core than on the inner wall face of the slot onthe axially central portion.

[0017] The insulating resin is coated to be thicker near an opening faceof the stator iron core on the inner circumferential side than any otherportion of the inner wall face of the slot.

[0018] The insulating resin is coated to take an R shape or chamferedshape on the axial end face of the stator iron core.

[0019] The insulating resin is coated to take an R shape or chamferedshape on the axial end face of the stator iron core.

[0020] The insulating resin on the axial end face of the stator ironcore is coated to be thicker on the inner diameter side of a core backneutral axis than on the outer diameter side.

[0021] The insulating resin on the inner wall face of the slot is coatedto be thinner on the outer circumferential side of the stator iron corethan any other portion of the inner wall face.

[0022] A notch is provided on the inner wall face of the slot on theouter circumferential side of the stator iron core, and the insulatingresin is coated to be thinner in the notch than any other portion of theinner wall face.

[0023] The axial end face of the stator iron core is formed in anirregular conformation.

[0024] The inner wall face of the slot is formed in the irregularconformation.

[0025] The insulating resin is coated to be thinner on the both ends ofthe laminated iron core in the circumferential direction than any otherportion of the laminated iron core.

[0026] The insulating resin is epoxy based insulating resin.

[0027] The insulating resin is silicone based insulating resin.

[0028] The stator coil is inserted into the slot to be aligned in onerow in a diameter direction of the stator iron core.

[0029] The stator coil has a substantially rectangular shape in crosssection.

[0030] The stator coil has a plurality of coils folded back outside theslot on the end face side of the stator iron core and wound to takealternately an inner layer and an outer layer in a slot depth directionwithin the slot for every predetermined number of slots, and a turnportion of the coil element wire folded back outside the slot on the endface side of the stator iron core is aligned in the circumferentialdirection to constitute a coil end group.

[0031] According to this invention, there is provided a method formanufacturing a stator for a rotary machine including a step of forminga laminated iron core by laminating a straight steel plate sheet with aslot shape punched, a step of coating an insulating resin at least on anaxial end face of a stator iron core and on an inner wall face of a slotin the laminated iron core, a step of forming the cylindrical statoriron core by placing the both circumferential ends of the laminated ironcore coated with the insulating resin into contact with each other, anda step of winding a stator coil around the stator iron core.

[0032] Also, according to this invention, there is provided a method formanufacturing a stator for a rotary machine including a step of forminga laminated iron core by laminating a straight steel plate sheet with aslot shape punched, a step of coating an insulating resin at least on anaxial end face of a stator iron core and on an inner wall face of a slotin the laminated iron core, a step of winding a stator coil around thelaminated iron core coated with the insulating resin, and a step offorming the cylindrical stator iron core by placing both circumferentialends of the laminated iron core having the stator coil wound intocontact with each other.

[0033] The insulating resin is applied by electrostatic powder coating.

[0034] The insulating resin is applied from an opening face of the sloton the inner circumferential side of the stator iron core.

[0035] The insulating resin is applied on the stator iron core in anaxial direction.

[0036] The stator coil is molded beforehand in an arranged state withinthe slot, and then inserted into the slot.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037]FIG. 1 is a perspective view showing a stator for a rotary machineaccording to an embodiment 1 of this invention.

[0038]FIG. 2 is a perspective view showing a part of a laminated ironcore in the stator for the rotary machine according to the embodiment 1of this invention.

[0039]FIG. 3 is a block diagram showing an electrostatic powder coatingapparatus for coating an insulating resin to the stator iron core in thestator for the rotary machine according to the embodiment 1 of thisinvention.

[0040]FIG. 4 is an external view and a cross-sectional view showing apart of the laminated iron core in the stator for the rotary machineaccording to the embodiment 1 of this invention.

[0041]FIG. 5 is a cross-sectional view showing a part of the laminatediron core in the stator for the rotary machine according to theembodiment 1 of this invention.

[0042]FIG. 6 is a perspective view showing a stator for a rotary machineaccording to an embodiment 2 of this invention.

[0043]FIG. 7 is a perspective view showing a method of assembling thestator for the rotary machine according to the embodiment 2 of thisinvention.

[0044]FIG. 8 is a perspective view showing a method of assembling thestator for the rotary machine according to the embodiment 2 of thisinvention.

[0045]FIG. 9 is a cross-sectional view showing a part of a laminatediron core in the stator for the rotary machine according to theembodiment 2 of this invention.

[0046]FIG. 10 is a cross-sectional view showing a part of the laminatediron core in the stator for the rotary machine according to theembodiment 2 of this invention.

[0047]FIG. 11 is a cross-sectional view showing the teeth in a statorfor a rotary machine according to an embodiment 3 of this invention.

[0048]FIG. 12 is a cross-sectional view showing the teeth in the statorfor the rotary machine according to the embodiment 3 of this invention.

[0049]FIG. 13 is across-sectional view showing the conventional rotarymachine.

[0050]FIG. 14 is a perspective view showing the stator for theconventional rotary machine.

[0051]FIG. 15 is a perspective view showing the coil element wire in thestator for the conventional rotary machine.

[0052]FIG. 16 is a perspective view showing the coil element wire in thestator for the conventional rotary machine.

[0053]FIGS. 17A and 17B are overall views showing the coil element wirein the stator for the conventional rotary machine.

[0054]FIGS. 18A and 18B are overall views showing the coil element wirein the stator for the conventional rotary machine.

[0055]FIG. 19 is a perspective view showing the laminated iron core inthe stator for the conventional rotary machine.

[0056]FIGS. 20A to 20C are perspective views showing a method ofassembling the stator iron core in the stator for the conventionalrotary machine.

[0057]FIG. 21 is a cross-sectional view showing a method of assemblingthe stator iron core in the stator for the conventional rotary machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0058] Now, a description will be given in more detail of preferredembodiments of the invention with reference to the accompanyingdrawings.

[0059] (Embodiment 1)

[0060]FIG. 1 is a perspective view showing a stator for a rotary machineaccording to an embodiment 1 of this invention. FIG. 2 is a perspectiveview showing a laminated iron core before being molded cylindricallyinto the stator as shown in FIG. 1. The stator 2 has a stator iron core15 with SPCC of 0.35 mm laminated, and a stator coil group 16 secured tothis stator iron core 15. The stator coil group 16 is composed of a longcoil element wire 30 bent like a thunder, as explained in the prior art.In the prior art, an electrical insulation between the stator coil 16and an inner wall face of a slot 15 a was made by the insulating paper19. However, in this invention, the insulating paper 19 is dispensedwith, and an insulating resin 100 is applied on the stator iron core 15to provide insulation between the stator coil 15 and the inner wall faceof the slot 15 a.

[0061] Herein, the application of the insulating resin 100 is desirablymade by electrostatic powder coating of an epoxy based insulating resin.The epoxy based insulating resin is more likely to permeate an appliedobject, and be coated uniformly. FIG. 3 is a schematic diagram forexplaining an electrostatic powder coater that is generally well known.As shown in FIG. 3, a powder coating material (herein epoxy resin as theinsulating resin 100) supplied to an electrostatic gun 50 by a feeder 51is electrified at a DC high voltage from an electrostatic voltagegenerator 52, and the electrified epoxy resin is coated on the appliedobject (herein a laminated iron core 150) with the air supplied from thefeeder 51 to the electrostatic gun 50. The laminated iron core 150 isgrounded, and the powder epoxy resin electrified negatively is attachedonto the stator iron core 15 with positive electric charges induced dueto an electrostatic pulling force. A desired part of the laminated ironcore 150 is masked, and the epoxy resin is coated onto a portioncorresponding to the stator iron core end face 15 f of the laminatediron core 150 and at least a part of the inner wall face of the slot 15a (i.e., a slanting line portion in FIG. 2). After coating the epoxyresin, the epoxy resin applied on the laminated iron core 150 is moltenby heating, and hardened in a baking furnace to form a continuous film.Herein, the insulating resin 100 is coated axially on the laminated ironcore 150 to form a relative thick film on the both end faces 15 f in theaxial direction.

[0062] As shown in FIG. 4, it is desirable that on the end faces 15 f,the insulating resin 100 is coated to be thicker on the inner diameterside of the core back neutral axis (the continuous line connecting thelocations without displacement on the end face 15 f when the straightlaminated iron core 150 is formed cylindrically) than on the outerdiameter side. This is because when formed cylindrically, the straightlaminated iron core 150 is displaced more greatly on the outer diameterside of the core back neutral axis than on the inner diameter side, andhence, if the insulating resin 100 is coated too thick, a crack is morelikely to occur. Even if the crack occurs on the outer diameter side ofthe core back neutral axis, the crack can be stopped near the core backneutral axis by coating the insulating resin 100 on the inner diameterside thinner than on the outer diameter side. Accordingly, it ispossible to prevent the cracking at the region where the resin crack isundesirable such as the opening edge of the slot 15 a.

[0063]FIG. 5 shows the axial cross section of the core back and theteeth 15 c as shown in FIG. 4. In this embodiment, on the axial end face15 f of the stator 8, the inner diameter side of the core back neutralaxis is 35μm, the outer diameter side is 20μm, and the axial centralportion of the inner wall face of the slot 15 a is 20μm. The insulatingresin 100 at the corner portion of axial end face of the slot 15 a is ofthe R shape to prevent the crack from being caused due to interferencewith the stator coil 16.

[0064] It is desirable that the insulating resin 100 is coated to bethinner on the circumferential both end portions 15 f of the laminatediron core 150 than any other portion. This is because the insulatingresin 100 is likely to cause a crack at the contact portion, and theinsulating resin 100 may be exfoliated from the teeth 15 c adjacent,when the cylindrical stator iron core 15 is later formed by bringinginto contact the circumferential both end portions 15 g of the laminatediron core 150. In addition, due to a gap of the contact portion, themagnetic resistance of the stator iron core 15 is aggravated, and hasadverse effect on the output. Accordingly, it is desirable that thecoating on this portion is suppressed as much as possible by masking.

[0065] In this way, the stator coil 16 formed by bending a coil elementwire 30 like a thunder is inserted into each slot 15 a of the laminatediron core 150 obtained by coating the insulating resin 100 as shown inFIGS. 15 to 21 for the conventional example. Herein, when the statorcoil 16 is inserted into the slot 15 a, it is aligned in one row in theradial direction of the stator iron core 15 within the slot 15 a.Thereby, the coil insertion is made regularly, and the stator coil 16can be prevented from abutting against the inner wall face of the slot15 a, and damaging the insulating resin 100, thereby improving theinsulating ability.

[0066] Further, the circumferential both end portions 15 g of thelaminated iron core 150 are brought into contact to form the cylindricalstator iron core 15, and to produce the stator 8 as shown in FIG. 1.

[0067] As described above, the electrical insulation between the statorcoil 16 and the inner wall face of the slot 15 a is made using theinsulating resin 100, in place of the insulating paper 19 asconventionally employed. Hence, the following effects can be obtained.

[0068] That is, in the conventional example, it took a lot of time toinsert the insulating paper 19 as insulating means into the laminatediron core 150. According to this invention, the insulating resin 100 maybe coated entirely onto the laminated iron core 150, whereby thelaminated iron core 150 can be simply treated for insulation, theoperation time is shortened, and additionally the insulating resin 100is cheaper in the material costs than the insulating paper 19, resultingin the products with the lower costs. Also, since the laminated ironcore 150 is straight, the opening portion 15 b on the innercircumferential side of the stator iron core 15 for the slot 15 a islargely opened, and the insulating resin 100 is easily coated.

[0069] Also, because of the coating of the insulating resin 100, therigidity of the stator iron core 15 is increased to prevent thedeformation of the teeth 15 c, whereby the stator coil is prevented fromcausing a short-circuit due to lower output caused by the deformation orrupture of the insulating paper 19. Also, since the rigidity of thestator iron core 15 is increased, the electromagnetic sound can bereduced.

[0070] The generated heat of the coil can be efficiently transmitted tothe stator iron core 15 via the insulating resin 100, and the coolingeffect can be improved. If the insulating paper 19 is employed, due tothe low thermal conductivity of the insulating paper itself and becausethe insulating paper 19 and the inner wall face of the slot 15 a are notsecured but contacted via the air, the thermal conductivity is reduced.However, since the insulating resin 100 has a higher thermalconductivity than the insulating paper 19, and the insulating resin 100and the inner wall face of the slot 15 a are secured withoutinterposition of the air, the generated heat of the coil can beefficiently transmitted to the stator iron core 15, thereby making itpossible to let the heat off to the bracket, and improve the coolingeffect.

[0071] Also, since the insulating paper 19 and the inner wall face ofthe slot 15 a are not secured together, when the water flows in from theoutside, it is apprehended that the water content sticks to the statoriron core 15, producing the rust to cause a false insulation. However,since the insulating resin 100 and the inner wall face of the slot 15 aare fully secured, there is a remarkable rust prevention effect becauseno water content permeates.

[0072] In the above embodiment 1, the insulating resin 100 is the epoxybased insulating resin. However, the silicone based insulating resinmaybe employed. The silicone based insulating resin has a greaterattenuation coefficient than the epoxy based insulating resin, givingrise to the effect that the insulating resin 100 is prevented fromcracking owing to the rotational oscillation of the generator. Also, theelectromagnetic sound can be reduced due to the oscillation attenuationeffect.

[0073] (Embodiment 2)

[0074]FIG. 6 is a perspective view showing a stator for a rotary machineaccording to an embodiment 2 of this invention. FIGS. 7 and 8 areprocess views of inserting a coil group into a stator iron core. In thisembodiment, unlike the above embodiment 1, there are three pairs ofstator coil groups 16 composed of a long copper wire 30 having arectangular cross section of 1.6 mm long×1.4 mm wide×R 0.2 mm at cornerpart.

[0075]FIG. 9 is an external view and a partial cross sectional view of astator iron core for a rotary machine in a circumferential direction ofslot, according to the embodiment 2 of this invention. As shown in FIG.9, the insulating resin 100 is coated to be thinner on the inner wallface of the slot 15 a on the outer circumferential side of the statoriron core than any other portion. This is because when the straightlaminated iron core 150 is formed cylindrically, the inner wall face ofthe slot 15 a on the outer circumferential side of the stator iron coreis displaced more greatly than any other inner wall face, and if theinsulating resin 100 is coated too thick, the crack is likely to occur.

[0076] A notch 15 h is provided on the inner wall face of the slot 15 aon the outer circumferential side of the stator iron core. Since due tothis notch 15 h, the displacement on the iron core in forming thestraight laminated iron core 150 cylindrically is concentrated on anotch portion 15 g, so that the displacement of other portion for thecore back can be suppressed, thereby preventing the exfoliation of theinsulating resin 100. Also, the laminated iron core 150 can be easilybent, and a high roundness can be obtained. Further, there is the effectof contributing to the attenuation of electromagnetic sound. Note thatwhen the insulating resin 100 is coated, the resin applied on the notch15 h is desirably thinner than any other portion on the inner wall faceof the slot 15 a. This is because when the laminated iron core 150 isbent, a displacement is concentrated near the notch 15 h, so that if theinsulating resin 100 is coated too thick, the crack is more likely tooccur. Note that even if the minute crack occurs, a short-circuitfailure is difficult to arise due to interference with the stator coilgroup 16, because of a space with the notch 15 h.

[0077]FIG. 10 is an axial cross sectional view of the core back portionand the teeth portion for the laminated iron core as shown in FIG. 9. Asshown in FIG. 10, the thickness of a laminated plate 15 d in the centralportion in a slot depth direction is 0.35 mm, while the thickness of alaminated plate 15 e at the end side is 0.5 mm, and the insulating resin100 near the opening edge of the slot 15 a is thicker, and formed in theR shape. When the stator coil 16 is inserted into the laminated ironcore 150 and formed cylindrically, the stator coil 16 makes contact nearthe opening edge of the slot 15 a on the end face of the stator ironcore 15 f. Hence, it is apprehended that an excessive stress is producedto damage the insulating film. The insulating resin 100 in this portionis thicker and of R shape, and the corner portion of the laminated plate15 e on the end side is tapered. Thereby, the stator coil 16 is lessdamaged near the opening edge of the slot 15 a, and the insulating resin100 is less exfoliated, to prevent the insulating film from beingdamaged, and improve the insulating ability.

[0078] As shown in FIG. 9, when the stator coil 16 is inserted into thelaminated iron core 150, or molded cylindrically, the insulating resin100 is formed thicker to secure the insulation near the opening edge ofthe slot 15 a on the inner circumferential side. In this way, the damageof the insulating film due to interference of the stator coil 16 withthe opening edge of the slot 15 a at the time of insertion, or theexfoliation of the insulating resin 100 can be prevented. Though the topend of the teeth 15 c is reduced or deformed circumferentially whenmolded cylindrically, the insulation can be also secured. In order toincrease the film thickness of the opening edge on the innercircumferential side, the insulating resin 100 is coated from theopening of slot 15 a on the inner circumferential side in thisembodiment, unlike the embodiment 1.

[0079] In this embodiment, the cross-sectional shape of the coil elementwire 30 is not circular as in the embodiment 1, but may be rectangular.When the coil element wire 30 has a circular cross section, the statorcoil 16 and the inner wall face of the slot 15 a are placed into pointcontact, due to circular cross section, producing an excessive stress atthe contact portion. However, if the coil element wire 30 has arectangular cross section in this embodiment, the stator coil 16 and theinner wall face of the slot 15 a are placed into line contact,suppressing excessive stress at the contact portion, so that theexfoliation of the insulating resin 100 and the damage of the insulatingfilm for the coil can be prevented.

[0080] (Embodiment 3)

[0081]FIG. 11 is a circumferential cross sectional view showing theteeth in the stator iron core of the stator for rotary machine accordingto an embodiment 3 of this invention. As shown in FIG. 11, an end face15 f of the stator iron core 15 is formed irregularly. Thereby, the endface 15 f of the stator iron core 15 and the insulating resin 100 arecontacted more intimately, and the exfoliation of the insulating resin100 can be prevented when the stator coil 16 is inserted into the slot15 a. Also, the formation of irregular shape may be made in a surfacetreatment process such as a shot process.

[0082] The same effects can be obtained by forming irregularities on theinner wall face of a slot 24 as shown in FIG. 11. The formation ofirregularities can be made, for example, by alternately laminating alaminated plate 360 d having a larger size in the circumferentialdirection of the stator iron core and a laminated plate 361 d having asmaller size, when the stator iron core 15 is fabricated by laminating asteel plate sheet with a slot shape punched. Also, the irregularitiesmay be formed by laminating the laminated plate having the same width inthe circumferential direction, alternately shifted. Also, theirregularities may be formed by making the corner portion of thelaminated plate 15 d like R shape, as shown in FIG. 12.

[0083] In the above embodiments, the insulating resin 100 is coated onthe laminated iron core 150, and the stator coil 16 is wound around thislaminated iron core 150, then both ends 15 g of the laminated iron core150 are brought into contact to form the cylindrical stator iron core15. However, the same effects can be obtained by winding the stator coil16 around the stator iron core 15 after forming the cylindrical statoriron core 15.

[0084] The stator coil is supposed to be a long coil element wire 30being like a thunder. However, the invention is not limited to suchstator coil. For example, various conductor segments (e.g.,substantially U character, substantially I character, substantially Jcharacter conductor segments) may be adopted to attain the same effects.A non-aligned wave winding may be employed as disclosed in JP-A-9-10352.In this case, a method may be taken of molding the stator coil in analigned state within the slot and inserting it into the slot asdisclosed in the same patent, thereby enabling the simple fabrication.

[0085] According to this invention, the stator iron core has a laminatediron core with a plurality of axially extending slots formed at apredetermined pitch along a circumferential direction, an insulatingresin is coated at least on an axial end face of the stator iron coreand an inner wall face of a slot in the laminated iron core to provideinsulation between the stator iron core and the stator coil, and thelaminated iron core is formed in a cylindrical shape by bringing bothcircumferential end portions of the laminated iron core into contactwith each other in such a way as to bend the laminated iron core so thatan opening face of the slot on the inner circumferential side may bedirected inside. Therefore, there is the effect that the stator for therotary machine has a high insulation and cooling performance, and can beproduced in a simple manner with high quality and low costs.

[0086] According to this invention, the insulating resin is coated to bethicker on the axial end face of the stator iron core than on the innerwall face of the slot on the axially central portion. Therefore, thereis the effect that the insulation film for the coil is prevented fromdamaging and the insulation property can be improved.

[0087] According to this invention, the insulating resin is coated to bethicker near an opening face of the stator iron core on the innercircumferential side than any other portion of the inner wall face ofthe slot. Therefore, there is the effect that the insulation film forthe coil can be prevented from damaging and the insulating resinprevented from exfoliating.

[0088] According to this invention, the insulating resin is coated totake an R shape or chamfered shape on the axial end face of the statoriron core. Therefore, there is the effect that the insulation film forthe coil is prevented from damaging and the insulation property can beimproved.

[0089] According to this invention, the insulating resin is coated totake an R shape or chamfered shape on the axial end face of the statoriron core. Therefore, there is the effect that the insulating resin canbe easily coated to take the R shape near the opening edge of slot.

[0090] According to this invention, the insulating resin on the axialend face of the stator iron core is coated to be thicker on the innerdiameter side of a core back neutral axis than on the outer diameterside. Therefore, there is the effect that the insulating resin can beprevented from cracking at the opening edge of slot.

[0091] According to this invention, the insulating resin on the innerwall face of the slot is coated to be thinner on the outercircumferential side of the stator iron core than any other portion ofthe inner wall face. Therefore, there is the effect that the insulatingresin can be prevented from cracking on the inner wall face of slot.

[0092] According to this invention, a notch is provided on the innerwall face of the slot on the outer circumferential side of the statoriron core, and the insulating resin is coated to be thinner in the notchthan any other portion of the inner wall face. Therefore, there is theeffect that the insulating resin can be prevented from cracking on theinner wall face of slot

[0093] According to this invention, the axial end face of the statoriron core is formed in an irregular conformation. Therefore, there isthe effect that the insulating resin can be contacted more closely withthe end face of the stator iron core and prevented from exfoliating.

[0094] According to this invention, the inner wall face of the slot isformed in the irregular conformation. Therefore, there is the effectthat the insulating resin can be contacted more closely with the innerwall face of slot and prevented from exfoliating.

[0095] According to of this invention, the insulating resin is coated tobe thinner on the both ends of the laminated iron core in thecircumferential direction than any other portion of the laminated ironcore. Therefore, there is the effect that the insulating resin can beprevented from cracking at the contact portion at the time ofcylindrical molding. Further, there is the effect that the magneticresistance is prevented from being worse by suppressing the occurrenceof gap at the contact portion.

[0096] According to this invention, the insulating resin is epoxy basedinsulating resin. Therefore, there is the effect that the insulatingresin is more likely to permeate the applied object and be coateduniformly.

[0097] According to this invention, the insulating resin is siliconebased insulating resin. Therefore, there is the effect that theelectromagnetic sound can be reduced owing to an oscillation attenuatingeffect.

[0098] According to this invention, the stator coil is inserted into theslot to be aligned in one row in a diameter direction of the stator ironcore. Therefore, there is the effect that the coil insertion is maderegularly, the insulating resin is prevented from damaging, and theinsulating property is improved.

[0099] According to this invention, the stator coil has a substantiallyrectangular shape in cross section. Therefore, there is the effect thatthe insulating resin is prevented from being damaged at the time ofmolding, and the stator coil can be easily bend and fabricated in asimple manner.

[0100] According to this invention, the stator coil has a plurality ofcoils folded back outside the slot on the end face side of the statoriron core and wound to take alternately an inner layer and an outerlayer in a slot depth direction within the slot for every predeterminednumber of slots, and a turn portion of the coil element wire folded backoutside the slot on the end face side of the stator iron core is alignedin the circumferential direction to constitute a coil end group.Therefore, there is the effect that the stator for the rotary machinecan be obtained with high quality and low costs.

[0101] According to the invention, there is provided a method formanufacturing a stator for a rotary machine including a step of forminga laminated iron core by laminating a straight steel plate sheet with aslot shape punched, a step of coating an insulating resin at least on anaxial end face of a stator iron core and on an inner wall face of a slotin the laminated iron core, a step of forming the cylindrical statoriron core by placing the both circumferential ends of the laminated ironcore coated with the insulating resin into contact with each other, anda step of winding a stator coil around the stator iron core. Therefore,there is the effect that the method for manufacturing the stator for therotary machine, in which the stator has a high insulating and coolingperformance, and can be fabricated in a simple manner, with high qualityand low costs.

[0102] Also, according to the invention, there is provided a method formanufacturing a stator for a rotary machine including a step of forminga laminated iron core by laminating a straight steel plate sheet with aslot shape punched, a step of coating an insulating resin at least on anaxial end face of a stator iron core and on an inner wall face of a slotin the laminated iron core, a step of winding a stator coil around thelaminated iron core coated with the insulating resin, and a step offorming the cylindrical stator iron core by placing both circumferentialends of the laminated iron core having the stator coil wound intocontact with each other. Therefore, there is the effect that the methodfor manufacturing the stator for the rotary machine, in which the statorhas a high insulating and cooling performance, and can be fabricated ina simple manner, with high quality and low costs.

[0103] According to the invention, the insulating resin is applied byelectrostatic powder coating. Therefore, there is the effect that theinsulating resin is more likely to permeate the applied object and becoated uniformly.

[0104] According to the invention, the insulating resin is applied froman opening face of the slot on the inner circumferential side of thestator iron core. Therefore, there is the effect that the film thicknessof the opening edge on the inner circumferential side can be formedgreater.

[0105] According to the invention, the insulating resin is applied onthe stator iron core in an axial direction. Therefore, there is theeffect that the insulating resin can be easily coated, and the statorcan be fabricated in a simple manner.

[0106] According to the invention, the stator coil is molded beforehandin an arranged state within the slot, and then inserted into the slot.Therefore, there is the effect that the stator can be fabricated in asimple manner.

What is claimed is:
 1. A stator for a rotary machine, comprising: arotor; and a stator having a stator iron core disposed oppositely aroundthe outer circumference of said rotor and a stator coil fitted aroundsaid stator iron core, wherein said stator iron core has a laminatediron core with a plurality of axially extending slots formed at apredetermined pitch along a circumferential direction, an insulatingresin is coated at least on an axial end face of said stator iron coreand an inner wall face of a slot in said laminated iron core to provideinsulation between said stator iron core and said stator coil, and saidlaminated iron core is formed in a cylindrical shape by bringing bothcircumferential end portions of said laminated iron core into contactwith each other in such a way as to bend said laminated iron core sothat an opening face of said slot on the inner circumferential side maybe directed inside.
 2. The stator for the rotary machine according toclaim 1, wherein the insulating resin is coated to be thicker on theaxial end face of said stator iron core than on the inner wall face ofthe slot on the axially central portion.
 3. The stator for the rotarymachine according to claim 1, wherein the insulating resin is coated tobe thicker near an opening face of said stator iron core on the innercircumferential side than any other portion of the inner wall face ofsaid slot.
 4. The stator for the rotary machine according to claim 1,wherein the insulating resin is coated to take an R shape or chamferedshape on the axial end face of said stator iron core.
 5. The stator forthe rotary machine according to claim 1, wherein the insulating resin iscoated to take an R shape or chamfered shape on the axial end face ofsaid stator iron core.
 6. The stator for the rotary machine according toclaim 1, wherein the insulating resin on the axial end face of saidstator iron core is coated to be thicker on the inner diameter side of acore back neutral axis than on the outer diameter side.
 7. The statorfor the rotary machine according to claim 1, wherein the insulatingresin on the inner wall face of said slot is coated to be thinner on theouter circumferential side of said stator iron core than any otherportion of said inner wall face.
 8. The stator for the rotary machineaccording to claim 1, wherein a notch is provided on the inner wall faceof said slot on the outer circumferential side of said stator iron core,and the insulating resin is coated to be thinner in said notch than anyother portion of said inner wall face.
 9. The stator for the rotarymachine according to claim 1, wherein the axial end face of said statoriron core is formed in an irregular conformation.
 10. The stator for therotary machine according to claim 1, wherein the inner wall face of saidslot is formed in the irregular conformation.
 11. The stator for therotary machine according to claim 1, wherein the insulating resin iscoated to be thinner on the both ends of said laminated iron core in thecircumferential direction than any other portion of said laminated ironcore.
 12. The stator for the rotary machine according to claim 1,wherein the insulating resin is epoxy based insulating resin.
 13. Thestator for the rotary machine according to claim 1, wherein theinsulating resin is silicone based insulating resin.
 14. The stator forthe rotary machine according to claim 1, wherein the stator coil isinserted into the slot to be aligned in one row in a diameter directionof said stator iron core.
 15. The stator for the rotary machineaccording to claim 1, wherein the stator coil has a substantiallyrectangular shape in cross section.
 16. The stator for the rotarymachine according to claim 1, wherein said stator coil has a pluralityof coils folded back outside said slot on the end face side of saidstator iron core and wound to take alternately an inner layer and anouter layer in a slot depth direction within said slot for everypredetermined number of slots, and a turn portion of said coil elementwire folded back outside said slot on the end face side of said statoriron core is aligned in the circumferential direction to constitute acoil end group.
 17. A method for manufacturing a stator for a rotarymachine, comprising the steps of: forming a laminated iron core bylaminating a straight steel plate sheet with a slot shape punched;coating an insulating resin at least on an axial end face of a statoriron core and on an inner wall face of a slot in said laminated ironcore; forming the cylindrical stator iron core by placing the bothcircumferential ends of said laminated iron core coated with theinsulating resin into contact with each other; and winding a stator coilaround said stator iron core.
 18. A method for manufacturing a statorfor a rotary machine, comprising the steps of: forming a laminated ironcore by laminating a straight steel plate sheet with a slot shapepunched; coating an insulating resin at least on an axial end face of astator iron core and on an inner wall face of a slot in said laminatediron core; winding a stator coil around said laminated iron core coatedwith the insulating resin; and forming the cylindrical stator iron coreby placing both circumferential ends of said laminated iron core havingsaid stator coil wound into contact with each other.
 19. The method formanufacturing the stator for the rotary machine according to claim 17 or18, wherein said insulating resin is applied by electrostatic powdercoating.
 20. The method for manufacturing the stator for the rotarymachine according to claim 17 or 18, wherein the insulating resin isapplied from an opening face of the slot on the inner circumferentialside of said stator iron core.